Q: How much carbon do websites produce?

According to a recent study, the median CO 2 emission per pageview is 0.79g for desktop and 0.69g for mobile devices. However, this number can go up to 3.09g for desktop and 2.76g for mobile at the 90th percentile ( source ). These figures are based on a single page visit. In reality, a web page can be accessed hundreds or even thousands of times a year, which can have a significant environmental impact. For instance, let's assume an average website that emits 0.79g CO 2 e per pageview and gets 5000 visits per month. In a year, this website would emit 0.79 x 5000 x 12 grams CO 2 e, which is equivalent to 47.4kg CO 2 e. This is comparable to boiling water for 6425 cups of tea (figures derived from Wholegrain Digital) or driving about 210 miles in a petrol or diesel car (a petrol or diesel car in the UK emits around 226g CO 2 e per mile. Source ). The new websites we create have much lower CO 2 emissions per pageview, ranging from 0.1g to 0.3g. This is well below the average. For example, one of our websites that emits 0.2g CO 2 e per pageview and has 5000 visits per month would only emit 0.2 x 5000 x 12 grams CO 2 e in a year, which is 12kg CO 2 e. This is just a quarter of the average. Please note that many of these figures are estimates and not exact measurements.

Q: What's the difference between CO 2 and CO 2 e?

Carbon dioxide (CO 2 ) is one of several greenhouse gases that contribute to global warming. Carbon dioxide equivalents (CO 2 e) is a term used to describe the total amount of greenhouse gases emitted, including CO 2 , methane, nitrous oxide, ozone, and water vapour. CO 2 e is a more accurate measure of the total impact of greenhouse gases on the environment than CO 2 alone. The global warming potential of each greenhouse gas is measured according to two major factors: how effective the gas is at trapping heat while in the atmosphere, and how long it remains there before breaking down. CO 2 is often used as a proxy for all of those other gases, whereas CO 2 e is more accurate, as it includes all the molecules that capture heat and warm our atmosphere.

Question 1

How much carbon does the internet produce?

Accepted Answer

The internet consumes a huge amount of electricity. According to estimates, it accounts for 3.7% of the global electricity production and the figure is rising (source and source). To put this in perspective, the internet uses more electricity than the UK.

Electricity is needed by internet servers, by networks that transmit data across the globe and by our mobiles, tablets, laptops and other devices we use.

Most of the electricity is generated from fossil fuels and thus contributes to significant carbon emissions in the atmosphere. Studies indicate that the carbon footprint of the internet is similar to (or higher than) the carbon footprint of the global aviation sector.

We can lower (or at least manage) this by enhancing the efficiency of websites and by using tools that help decrease server load. But, like recycling, the more people that do this, the better the outcome for the environment.

YOu can find out more on our Sustainable web design page.

Question 2

How much carbon do websites produce?

Accepted Answer

According to a recent study, the median CO₂ emission per pageview is 0.79g for desktop and 0.69g for mobile devices. However, this number can go up to 3.09g for desktop and 2.76g for mobile at the 90th percentile (source). These figures are based on a single page visit. In reality, a web page can be accessed hundreds or even thousands of times a year, which can have a significant environmental impact.

For instance, let's assume an average website that emits 0.79g CO₂e per pageview and gets 5000 visits per month. In a year, this website would emit 0.79 x 5000 x 12 grams CO₂e, which is equivalent to 47.4kg CO₂e. This is comparable to boiling water for 6425 cups of tea (figures derived from Wholegrain Digital) or driving about 210 miles in a petrol or diesel car (a petrol or diesel car in the UK emits around 226g CO₂e per mile. Source).

The new websites we create have much lower CO₂ emissions per pageview, ranging from 0.1g to 0.3g. This is well below the average. For example, one of our websites that emits 0.2g CO₂e per pageview and has 5000 visits per month would only emit 0.2 x 5000 x 12 grams CO₂e in a year, which is 12kg CO₂e. This is just a quarter of the average.

Please note that many of these figures are estimates and not exact measurements.

Question 3

What's the difference between CO₂ and CO₂e?

Accepted Answer

Carbon dioxide (CO₂) is one of several greenhouse gases that contribute to global warming. Carbon dioxide equivalents (CO₂e) is a term used to describe the total amount of greenhouse gases emitted, including CO₂, methane, nitrous oxide, ozone, and water vapour.

CO₂e is a more accurate measure of the total impact of greenhouse gases on the environment than CO₂ alone. The global warming potential of each greenhouse gas is measured according to two major factors: how effective the gas is at trapping heat while in the atmosphere, and how long it remains there before breaking down.

CO₂ is often used as a proxy for all of those other gases, whereas CO₂e is more accurate, as it includes all the molecules that capture heat and warm our atmosphere.

Question 4

Why do some websites produce more carbon than others?

Accepted Answer

There are several reasons why websites consume more power and create more carbon emissions. One of the common culprits is the way images are handled. When a web page includes images, they are usually sent individually over the internet. If the images are larger than the space available on the receiving device, then data is being transmitted unnecessarily, which uses more power and creates more carbon emissions.

There are other inefficiencies built into many websites which is why these use more power either on the server or the network leading to greater CO₂e emissions.

Question 5

What are the benefits of a sustainable website?

Accepted Answer

There are several benefits to reducing the carbon footprint of your website. Firstly, it can make a positive difference to the environment by reducing carbon emissions. Typically, we can reduce the carbon footprint to 0.3g CO₂e/pageview or less. This could be a large reduction depending on the existing characteristics of your site.

Secondly, by reducing the amount of data transferred over the internet, the response time of your web pages will improve. This is beneficial for users, and there are several studies that show that poor response times result in a higher percentage of people abandoning a website.

Thirdly, search engines prefer to promote websites with faster response times because people don't want to have to wait for the information they want. So, all other things being equal, faster websites will appear higher in the search engine results.

In addition, it shows that a business prioritises environmental issues and is committed to sustainability practices.

Question 6

Are low-carbon websites better for SEO?

Accepted Answer

Generally, yes, simply because they're faster. Reducing the quantity of data transmitted over the internet is an important aspect of creating a low-carbon website.

One way to achieve this is by ensuring that any images are correctly sized for the device they will be displayed on. There is no point sending a 1200 pixel wide image to a mobile phone that has a screen that is only 400px wide. This is inefficient and wasteful. By improving efficiency, the load time of pages goes down, which can lead to a better user experience.

Users prefer faster websites and search engines prioritise user experience, so slower web pages tend to move down the search engine results listings while faster ones move higher.

Question 7

How do sustainable websites contribute to a business's carbon reduction plans?

Accepted Answer

It is possible to estimate the carbon emissions of a website, and we always measure the before and after position of the pages of sites we work on. If you know how many visits each page gets every year (from your analytics), you can easily calculate the reduction in CO₂e emissions resulting from the work on the website. If you are a business that offsets your carbon emissions by planting trees or other activities, you may be able to reduce the amount you spend on this if you have a low-carbon website 12.

Question 8

Can a website be powered by renewable energy?

Accepted Answer

Yes. There are a number of hosting companies that power their data centres using renewable energy sources and in some cases, a business can choose. Some websites (e.g. Shopify) include hosting in their service so a website on that platform cannot choose a green hosting company. In 2022, around 10% of websites were hosted with companies that used green energy (source).

That covers hosting but we also need to consider the network. Here, the choice rests with the user (although, in reality, there's probably little difference between suppliers). Their mobile may be on O2 or Vodafone and their broadband provider may be BT. As far as I can ascertain, no network provider runs their service on renewable energy.

Therefore, even with green hosting, every effort must be made to reduce the data transmitted over the network to reduce the carbon emissions of a website.

Question 9

How does SEO contribute to reduce digital carbon footprint of the web?

Accepted Answer

An SEO-optimised site will be found more easily in the search engines for relevant searches. Therefore, if someone is searching for the products or services you offer and they find your site easily and quickly, fewer searches will be needed and/or fewer pages of search results will be returned. This means less work on servers and less data transmission, hence less electricity needed leading to lower carbon emissions.

Question 10

What do you do to create a sustainable website?

Accepted Answer

From a technical perspective,

we ensure your site is hosted with a company that powers their servers with renewable energy
we create multiple versions of every image on your site and make sure we deliver the best sized image in the best format for the device requesting it
we optimise the code running on the server to make it as efficient as possible
we optimise font files and other code to keep them as small as possible
we ensure all resources are loaded in the optimal way
we enable caching so devices don't always have to get resources from the server.
etc.

Question 11

What process do you follow?

Accepted Answer

The exact process will depend on the specifics of the project but as a minimum we will:

Conduct a discovery phase where we will gain a greater understanding of the business, it's aims and objectives and, in particular the goals of the website. This phase also includes an analysis of competitors, an understanding of what the website needs to include and the client's design ideas.
Undertake keyword research for the client to find the best phrases used by people to find the products and/or services offered by the client
Produce initial designs for the new site
Support the production of the website content, in particular the use of keywords in content.
Build web pages
Test web pages for appearance, function, performance and carbon emissions.
Plan the migration from the old site to the new site.
Move new site live
Test and check that all is well. Test performance and carbon emissions on live server.

You can find more information on our website creation page

Question 12

Can you make changes to my existing site to reduce its carbon emissions?

Accepted Answer

Possibly. Some web platforms make it very difficult to make worthwhile improvements aimed at reducing carbon emissions e.g. Shopify. However, many other platforms do allow a wider range of changes both to the website and the hosting where significant carbon savings could potentially be made.

We evaluate this on a case-by-case basis and would be happy to take a look at your site to see what can be done. Please do contact us and give us some brief details.

Question 13

What does a website have to sacrifice to be low carbon?

Accepted Answer

In most cases the answer is nothing. It's perfectly possible to create an attractive, fast, secure and effective website that is also low-carbon. A low-carbon website is certainly NOT an unattractive, boring site with no images!

Question 14

How much does it cost to have a new low-carbon website?

Accepted Answer

The answer is that it depends! A simple 10 page website is not going to cost as much as a complex ecommerce site with 500 products on sale. The cost will depend on the scope and complexity of the website you have in mind and also whether you'd like us to work on search optimisation.

Please contact us and let's have a conversation about your plans. We will then be in a better position to give you an idea of costs.

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